Evaluate the following expression when $d = 6$ and $c = 3$. $3$ $d$ $ + 3$ $c$ $ + 3$
Answer: Substitute $6$ for ${d}$ and $3$ for ${c}$ $ = 3{(6)} + 3{(3)} + 3 $ $ = 18 + 9 + 3 $ $ = 30$